Download File

1
Foundations
of physical
activity
1
Body systems
and energy for
physical activity
In this chapter a student:
1.1 discusses factors that limit and enhance the capacity to move and perform
1.2 analyses the benefits of participation and performance in physical activity and sport
4.1 works collaboratively with others to enhance participation, enjoyment and performance
4.2 displays management and planning skills to achieve personal and group goals
4.3 performs movement skills with increasing proficiency
4.4 analyses and appraises information, opinions and observations to inform physical activity
and sport decisions
To play sport and be physically active we need to move our body with relative ease and without
undue stress. Our body systems play an important role to work together to efficiently move the body
according to our body type, coordination and fitness level. The function of the skeletal, muscular,
circulatory and respiratory systems all play a vital role in allowing our body to live and move
effectively. This chapter outlines the importance of each system and explains how each system
works together to allow the efficient movement of the human body. It examines how the body works
to use energy for efficient movement and the relationship of the body systems that function together
to allow movement for physical activity to occur.
Structure and function of the skeletal system
The skeletal system is the bone structure of the body. The adult human
body consists of 206 bones; however, not all of these are used to perform
physical activity. An infant has 350 bones, as they are not yet fused together.
Figure 1.2 shows the names of all of the skeletal bones that contribute to the
support and, together with the muscular system, the movement of the body.
The skeletal system is made up of two main sections, the axial skeleton and
the appendicular skeleton, both of which are important to the movement of
the body. The axial skeleton includes the skull, spine and thorax. This section
of the skeletal system provides support and movement of the upper body
(see the orange section of figure 1.2 on page 4). The appendicular skeleton
Body systems and energy for physical activity
Chapter
1
includes the bones of the upper and lower arms, the wrists and hands,
the pelvic area, the upper and lower legs, and the feet. All of these bones
enable the body to be upright and supported, and they work together with
the muscles to enable movement while the body is stationary or travelling
through space (see Table 1.1 on pages 10 and 11).
Role of the skeletal system
The skeletal system contributes greatly to the movement of our body.
Why do you think the
The spine supports our head and allows trunk rotation, together with
skeleton has been
the voluntary movement of our arms, legs, feet and hands according to
classified as axial and
the sport or activity we wish to perform.
appendicular?
Bones are very important to movement for physical activity and
exercise can strengthen our bones, along with the intake of calcium-rich
foods. Bones are the inner support system of the body. They provide a rigid
structure for the body and, along with the joints and muscles, help the body to
move effectively. Figure 1.1 shows the structure of a bone—it is a very simple
structure, yet a very important one. The bones in our body are all alive and the
end of the bone shown in figure 1.1 has a growth plate that is very important
to the growth of the bone. If the growth plate is damaged the growth of the
bone may be stunted and physical problems can occur. For example, damage
of the growth plate in one femur bone (upper leg) could cause reduced
growth in one leg, resulting in one leg being shorter than the other.
Figure 1.1 Structure of a femur bone
Head of bone
Spongy
bone
Growth
plate
Compact bone
Marrow cavity
Shaft
Learning
experience
How well do you know the bones of the body?
The box of bones pictured on page 4 is in
need of recognition. Identify each bone using
the list below and check your answers by
using the picture of the skeletal system that
follows (figure 1.2).
• Cranium (skull)
• Sternum (breast bone)
• Ribs (mid region of the body)
• Radius and ulna (lower arm)
• Femur (upper leg)
• Tibia and fibula (lower leg)
• Tarsals, metatarsals and phalanges
(ankles, feet and toes)
• Patella (knee)
• Carpals, metacarpals and phalanges
(wrist and hands)
• Pelvis (lower mid region—hip bones)
• Vertebral column (spine)
• Humerus (upper arm)
• Clavicle (collar bone)
Move into PASS
PART 1 Foundations of physical activity
Cranium (skull)
Figure 1.2
Clavicle (collar bone)
Mandible (jaw)
The skeletal system
01002
Sternum (breast bone)
Scapula (shoulder blade)
Ribs
Humerus (upper arm)
Spine (vertebral column)
Radius (lower arm)
Pelvis (hip bone)
Ulna (lower arm)
Webconnect
Carpals
Check your understanding
of the location of bones by
visiting the following interactive
website: <www.innerbody.
com/image/skelfov.html>.
Phalanges
Metacarpals
Femur (thigh bone)
Patella (kneecap)
Tibia (lower leg)
Fibula (lower leg)
Tarsals
Phalanges
Metatarsals
01003
Body systems and energy for physical activity
Types of bones and joints
There are several different types of bones in the body. Some types vary in
size and each have an important role to play in support and movement of the
body. For example, long bones in the legs work with the joints and muscles to
allow the body to stride out and extend when walking or running.
The bones in the body are classified by their shape and are grouped into
six types: long, short, flat, irregular, sesamoid and sutural (see figure 1.2 for
more detail).
Long bones are long and slightly curved for strength, and can be found in
the arms and legs. The femur is an example of a long bone.
Short bones are small and nearly equal in length and width. They can be
found in the wrist and ankles. Tarsals are short bones.
Flat bones are generally thin and flat, with the purpose of protecting vital
organs. For example, the skull is a flat bone that protects the brain and the
sternum and ribs are flat bones that protect the heart and lungs.
Irregular bones are an unusual shape and are not like any other bones
mentioned above. For example, the bones that make up the spine
(vertebrae) and some facial bones are categorised as irregular bones.
Sesamoid bones are small and must cope with considerable stress at times.
Examples of sesamoid bones are those in the tendons of the knee (patella)
and wrist.
Sutural bones are somewhat immovable and are small bones found in
the skull.
Bones are held together by connective tissue that allows movement between
the joints. Joints that are relied on for movement in physical activity contain
connective tissue that allows muscles and bones to work together to move.
There are many types of joints that allow various parts of the body to move in
many different ways. The type of joint that is located at the point where one
bone meets another is determined by the movement it needs to make when a
muscle contracts or relaxes. The size of the joint, or area that exists between
two bones that meet, is a key factor that determines how much movement will
occur at that joint. The more space between the two bones, the greater the
movement. For example, the knee joint has a lot of connective tissue between
and around the joint and therefore has a large range of movement. It is also a
site of potential injury, as this larger space of connective tissue can be placed
under a lot of strain during exercise. This is why knee injuries are common in
sports that require a lot of running or change in direction.
In some parts of the body, movement can be restricted by the type of joint
and by the degree of movement that joint allows. For example, the bones of
the elbow are connected by a hinge joint that allows quite limited movement
in one direction only. However, the shoulder has a ball and socket joint, which
is the joint with the largest range of movement. When a person exercises, the
way in which they move is restricted by six
moveable joints, known as synovial joints.
These joints and the range of movement
Evaluate why the bones
they allow for are outlined in figure 1.3.
of the body are a specific
shape, given their
location in the body.
Chapter
1
Move into PASS
PART 1 Foundations of physical activity
Gliding joint
Carpals
Hinge joint
Humerus
Radius
Ulna
Pivot joint
Axis
Allas
Transverse ligament
Dens
Condyloid joint
Metacarpal
Phalange
Saddle joint
First metacarpal
Trapezium
Ball and socket joint
Hipbone
Head of femur in acetabulum
Femur
Figure 1.3
from Hole’s human anatomy and physiology, (1999), 8th edn, Shier, Butler and Lewis
Six moveable joints
of the body
Learning experience
1 Match the following bones up
with their type using the
table opposite.
Type of bone
Name of bone
Long bone (L)
Tarsal
Short bone (Sh)
Patella
Flat bone (F)
Femur
Irregular bone (I)
Scapula
Sesamoid bone (SB)
Vertebra
Body systems and energy for physical activity
Chapter
1
2 Study the diagram of the skeletal system (figure 1.2) and complete the table
below by naming the types of bones and their function during exercise.
Name of bone
Type of bone
Function during exercise
Vertebral column
Femur
Cranium
Pelvis
Ribs
Carpals
Tarsals
Tibia
Radius
Ulna
Clavicle
Scapula
Patella
Humerus
Basic contribution to efficient movement
The skeletal system is the inner core for stable movement of the body. Bones
provide the internal frame for our muscles and joints to work together to
perform voluntary movement. To enable our body to move efficiently, the
skeletal system provides support and leverage so that wellbalanced movement can occur. For example, to run in a
well-balanced way an athlete needs to use the stability of the
skeletal system, in combination with the muscular system,
Visit the following website and build a
from the position of the head, shoulders, arms and midline,
skeleton: <www.ehc.com/vbody.asp>.
as well as extension and flexion of the hip, knee, ankle and
What does the skeleton do when you
toes, to stride out and run well. The skeletal system is our
have completed the structure?
main support structure in all physical activities.
Webconnect
Structure and function of the muscular system
The muscular system is a voluntary system. For movement to occur, the
muscular system requires not only our will to move but also signals from our
brain, sent by the central nervous system, which communicate that movement
in a muscle should take place. In order for our body to participate in sport
and physical activity, it needs to move effectively by combining the use of the
Move into PASS
PART 1 Foundations of physical activity
Figure 1.4 The major muscles of the muscular system
8 Pectoralis major
1 Deltoids
2 Biceps
9 Latissimus dorsi
3 External
oblique
10 Biceps
11 Abdominals
12 Brachioradialis
4 Wrist
flexors
19 Trapezius
5 Hip flexors
13 Rhomboid
major
6 Quadriceps
20 Triceps
14 Lattissimus
dorsi
7 Tibialis anterior
21 Wrist
extensors
15 Illiotibial tract
22 Gluteus maximus
16 Hamstrings
17 Gastrocnemius
23 Soleus
18 Calcaneal tendon
Body systems and energy for physical activity
Chapter
1
skeletal system, joints and muscles. The joints and muscles must voluntarily
contract (tighten the muscle) and relax the muscle group to perform a
selected movement. These movements can be discrete (one movement)
or continuous (repeated movements).
Role of the muscular system
The role of the muscular system is to allow for movement to participate
in day-to-day activities, and to perform sports and physical activity. The
muscular system combines with the skeletal and circulatory systems to
perform voluntary movements. The more movement muscles perform, the
stronger and more efficient they become. This is known as a training effect.
For example, a trained muscle will perform better than an untrained one.
If the muscles stop training they become weaker, and reduce in size and
efficiency. This is why an athlete needs to keep training to stay in good
shape for competition.
Figure 1.5
Bicep curl
Muscle movement
An example of the way a muscle uses
contraction and relaxation to move or lift an
object is the performance of a bicep curl. To
perform a bicep curl with a hand weight, the
hand needs to extend (open up) and hold the
weight, and then contract to grip it. The arm
is in a straight and slightly flexed position
that is called an extended position. The hand
is then raised towards the shoulder and the
arm is flexed (bent toward the shoulder at the
elbow)—contraction of the bicep muscles allows
the weight to be raised. To lower the weight, the biceps relax and
the triceps contract. The bicep and tricep muscles work together
to perform the movement. (This action is illustrated in figure 1.5.)
Many muscles work in groups like this, opposing each other to
effectively perform a movement.
Flexion
Extension
01006
Movement terms
Our body moves in different directions when we choose to
perform an action. Table 1.1 outlines the way in which we
describe the motion of the body and body parts. These terms are
very important to describe what is happening during a physical
activity skill. For example, a cyclist can be analysed for their
flexion or extension at the hip, knee and ankle, and suggestions
made to increase or decrease this movement to improve their
performance.
To analyse movements, it is a good idea to think of each being
performed starting in the anatomical position (standing with
your hands by your side, with your thumbs facing outwards—
see figure 1.6). All of the joint actions outlined in table 1.1 are
performed using this starting position.
Figure 1.6
01007
The
anatomical position
10
Move into PASS
PART 1 Foundations of physical activity
Table 1.1 Joint actions
Joint action
Description of the joint action
Flexion
An action involving the angle between
two bones decreasing with the
movement
Extension
An action involving the angle between
two bones increasing with the movement
(it is the opposite of flexion)
Abduction
01008
An action that involves movement away
from the middle of the body
01009
Adduction
An action that involves movement
towards the middle of the body
01010
Pronation
(inversion)
An action where the foot or hand is
turned inward
01011
Body systems and energy for physical activity
Joint action
Description of the joint action
Supination
(eversion)
An action where the foot or hand is
turned outward (it is the opposite of
pronation)
Rotation
An action performed by turning the
upper body or head to one side
Chapter
01013
Circumduction
An action that is similar to rotation but
involves the circular motion of a limb
01014
Plantar flexion
An action of the foot, where the toes are
pointed forward (for example, pressing
on an accelerator when driving)
01015
Dorsi flexion
An action of the foot, where the toes are
lifted upward (for example, taking your
foot off an accelerator when driving and
pointing the toe toward the knee; it is the
opposite of plantar flexion)
01016
1
11
12
Move into PASS
PART 1 Foundations of physical activity
Learning experience
1 Stand in the anatomical position to start
(see figure 1.6), and carefully perform all
of the movement terms outlined in table
1.1 one at a time. Note the various body
parts you use and refer to the joint actions
in figure 1.3 for more information about the
movements at the joints.
2 Copy table 1.1 into your workbook,
adding a third column to the right,
titled ‘Sport example’. Complete the table,
providing an example of an action performed
in a sport that uses each movement in the
table. (The example for flexion is completed
for you below.)
Joint action
Description of the joint action
Sport example
Flexion
An action involving the angle between two
bones decreasing with the movement
Cycling involves flexion at the
torso, hip, knee and ankle
Structure of voluntary muscles
Unlike the heart muscle, which is an involuntary muscle, the skeletal muscles
are voluntary (movement is initiated by choice). These muscles rely on joint
mobility with the skeletal bones for leverage. This joint mobility exists because
of the tendons that attach muscles to bones through connective tissue, and the
type of connective tissue depends on the joint connecting the bones.
Basic contribution to efficient movement
There are several types of muscle fibres. The most important ones to sport
and physical activity are fast twitch fibres for fast and short exercise, and slow
twitch fibres for long duration and slow- to medium-paced physical activity.
A sprinter will have more fast twitch fibres than an endurance athlete and the
making of elite athletes will be determined by their ratio of these fibres, along
with their body type and talent. Everyone has both fast and slow twitch fibres
and training can enhance the performance of these fibres. This is why one
athlete may seem like a natural sprinter while another may seem to be natural
endurance athlete. Suitability to a particular sport comes down to the ratio of
fibres in the body as well as the anatomical body type suited to a sport, along
with natural talent and hard training.
Learning experience
After participating in an adequate warm-up,
perform a repeated activity like step-ups,
crunches or push-ups. Try to work continuously
at a medium to hard intensity until you feel
an uncomfortable burning sensation in your
muscles and you cannot go any further.
This is an example of anaerobic exercise and
your lactate system, or anaerobic energy system,
is telling your body to stop. If an athlete tries to
push through this phase of exercise they
will only be able to do so for a short period of
time. The muscles will not feel comfortable at
this phase of exercise and the burning sensation
is a signal from the body that the intensity of the
movement must be reduced or it will shut down
and/or become injured. This is the body’s in-built
safety system and if an athlete pushes beyond
this injury or collapse may result.
Body systems and energy for physical activity
Chapter
1
Structure and function of the circulatory system
The circulatory system is a very complex system that relies on the heart
and lungs to circulate blood, oxygen and waste products around and out
of the body. During exercise this system works very efficiently to circulate
oxygen to the working muscles by pumping blood through the heart muscle.
This important system also eliminates waste products such as carbon dioxide,
water and, in anaerobic exercise, lactic acid.
The heart is the centre of the circulatory system. It is a smooth muscle that
is positioned in the centre of our chest and is on ‘automatic pilot’. This means
that without instruction from the brain the heart will keep pumping blood
around our body twenty-four hours a day, seven days a week, non-stop.
Figure 1.7 demonstrates the cycle within the circulatory system.
Role of the circulatory system
The circulatory system regulates the blood circulation around the body, to
transport oxygen to our muscles during exercise. When we are in a relaxed state
our heart will pump slower than when we move around or perform vigorous
exercise. When we exercise, the speed at which blood is pumped around our
body is increased and our heart rate rises considerably. A heart that is working
with ease is said to be an efficient one and the fitness of an athlete, particularly
an endurance athlete, is an indicator of an efficient circulatory system.
Major components of the circulatory system
The following diagram illustrates the lungs, heart and body that make up the
components of the circulatory system.
Figure 1.7
The circulatory
system
Webconnect
1 Visit the following site to observe
the circulatory system in motion:
<http://library.thinkquest.
org/11965/html/cyber-anatomy_
car691.html>.
2 Visit the following site and observe
an animated heart at work:
<www.ehc.com/vbody.asp>.
3 After visiting the sites listed above,
copy figure 1.7 into your workbook.
Draw arrows on the diagram to
indicate the flow of blood and
oxygen in the circulatory system.
01018
13
14
Move into PASS
PART 1 Foundations of physical activity
Basic contribution to efficient movement
In order to participate in physical activity and sports we need an efficient
circulatory system. The heart and lungs work together to efficiently pump
oxygen-rich blood around the body and filter the waste products from
deoxygenated blood. The circulatory system is very important to our aerobic
energy system and the way in which we use energy.
During exercise the heart will work much harder than at rest and a trained
athlete will have a strong, fit heart to support their body during physical
activity. If an athlete is physically fit they will have an efficient target heart rate
for exercise and a relatively low resting heart rate (pulse). The average pulse
rate for a fit teenager ranges between 60 and 70 beats per minute.
Pulse facts
A pulse is a measure of the beats your heart takes to pump blood around the
body. It is usually measured at the radial (wrist) or carotid (neck) sites on the
body. Your true resting pulse should be taken before you get up, after a good
night’s sleep.
Factors that can affect pulse rates include digestion (processing food after
eating), stress, sickness and fatigue, as they can all increase the pulse rate
because the body is working harder to recover from these situations.
Learning experience
Perform an adequate warm-up and then
complete the following steps for sections A
and B to see how well your body copes with
the demands of exercise. Record your results
in your workbook.
4 Raise your heart rate by stepping as fast as
possible for 2 minutes. Take your heart rate
immediately after stopping and record the
number of beats per minute. (This is
Step HR 2 on the graph.)
Section A
5 Walk slowly for 1 minute and then rest for
5 minutes. Take your recovery heart rate at
the end of this rest and record the number
of beats per minute. (This is Rec. HR 2 on
the graph.)
Complete the following tasks to determine
your heart rate efficiency and estimate your
fitness level.
1 Take your resting heart rate (pulse) and
record the number of beats per minute.
(This is RHR on the graph.)
2 Raise your heart rate by stepping onto
and back off a step as fast as possible for
2 minutes. Take your heart rate immediately
after stopping and record the number of
beats per minute. (This is Step HR 1 on
the graph.)
3 Walk slowly for 1 minute and then rest for
5 minutes. Take your recovery heart rate at
the end of this rest and record the number
of beats per minute. (This is Rec. HR 1 on
the graph.)
6 Calculate your maximum heart rate using
the following formula:
220 – your age = beats per minute.
(This is MHR on the graph.) Using the details
you recorded in steps 1–5, work out how far
off your maximum heart rate you were for
each activity.
Section B
Using a line graph like the one on page 15,
plot your results from section A and discuss this
activity with your class.
Body systems and energy for physical activity
Exercise and recovery heart rates
Beats
per minute
210
200
190
180
170
160
150
140
130
120
110
100
90
80
70
60
RHR
Step
HR 1
Rec.
HR 1
Step
HR 2
Rec.
HR 2
MHR
Results
Structure and function of the respiratory system
The respiratory system consists of cavities that allow air to travel to our lungs
and is a very effective system to supply oxygen to the body. The cavities
and tubes of the respiratory system lead to our lungs and end with the very
important alveoli (air sacks)—the point where oxygen is transported into
our blood. The respiratory system works closely with the heart to create an
efficient circulatory system.
Role of the respiratory system
The respiratory system supplies oxygen to all parts of the body. It supplies
oxygen to our muscles to allow movement and oxygen to the brain to allow
proper functioning of our body every second of every day. This system is
very important for efficient aerobic exercise. It supplies oxygen to the body
for all forms of exercise and is vitally important to all athletes, particularly
endurance athletes whose main source of energy is oxygen.
Chapter
1
15
16
Move into PASS
PART 1 Foundations of physical activity
Major components of the respiratory system
The respiratory system extends from the mouth and nose, which inhale and
exhale air that moves through the larynx and trachea to the left and right
bronchus and, bronchioles and finally to transfer oxygen to the blood at the
alveoli. The movement of air in and out of the body is created by pressure
that is regulated by the movement of the diaphragm (the muscle below the
lungs). This muscle moves down and the ribs rise to allow air to move into the
body (inhale). The opposite effect is performed in breathing out (exhaling) by
raising the diaphragm and lowering the ribs to force the air from the body.
Learning experience
1 Copy figure 1.8 into your workbook. Draw an
arrow from the mouth/nose to the alveoli
to indicate the direction of the air when
this person inhales (breaths in) to show
the movement and transfer of oxygen. Then
draw an arrow to indicate the direction of
the diaphragm (the muscle under the lungs)
when a breath is inhaled.
2 Discuss with your classmates some reasons
why the respiratory system might not work
as well as it should when exercising. For
example, asthma will restrict breathing
during exercise. Can you think of other
factors that could help or hinder the
respiratory system?
Figure 1.8
The respiratory system
Nasal cavity
Oral cavity
Tongue
Pharynx
Epiglottis
Larynx
Esophagus
Trachea
Right bronchus
Left bronchus
Lung
Ribs
Bronchiole
Diaphragm
Mucus
Air sac
(alveolus)
Cells
Capillaries
01020
Body systems and energy for physical activity
Chapter
1
Basic contribution to efficient movement
In order to exercise efficiently we need to train our body and this includes our
lungs. A trained athlete has a high lung capacity and will be able to transport
oxygen with ease into the working muscles to enable efficient movement
when exercising.
An asthmatic is a person who has an impaired lung capacity and will have
to work harder to allow air to travel through the bronchioles, as their tubes are
restricted by the condition of asthma.
Learning experience
This activity will indicate how well your lungs perform while participating in physical activity.
Perform an adequate warm-up and then complete the following steps for sections A and B to
see how well your body copes with the demands of exercise. Record your results in your workbook.
Section A
Complete the following tasks to determine your breathing rate efficiency and estimate your
fitness level.
1 Count the number of breaths that you expire (breath out) in one minute to determine your resting
expiry rate and record the number of expirations per minute. (This is RER on the graph.)
2 Raise your heart rate by stepping onto and back off a bench as fast as possible for 2 minutes.
Take your expiration rate immediately after stopping and record the number of expirations
per minute. (This is Step ER 1 on the graph.)
3 Walk slowly for 1 minute and then
rest for 5 minutes. Take your
expiration rate at the end of this
rest and record your recovery
breathing rate as expirations per
minute. (This is Rec. ER 1 on
the graph.)
4 Raise your heart rate by stepping
as fast as possible for 2 minutes.
Take your expiration rate
immediately after stopping and
record the number of expirations
per minute. (This is Step ER 2 on
the graph.)
5 Walk slowly for 1 minute and then
rest for 5 minutes. Take your
expiration rate at the end of this
rest and record the number of
expirations per minute. (This is
Rec. ER 2 on the graph.)
Section B
Using a line graph like the one below,
plot your results from section A and
discuss this activity with your class.
Expiration rate for exercise and recover
Expirations
per minute
180
170
160
150
140
130
120
110
100
90
80
70
RER
Step
ER 1
Rec.
ER 1
Step
ER 2
Rec.
ER 2
Breaths expired in one minute at each part
17
18
Move into PASS
PART 1 Foundations of physical activity
Energy and physical activity
‘You are what you eat.’ This saying indicates that what you put into your body
is what you will get out of it—by eating healthy foods, you will look and feel
much better. The intake of energy (the food we eat) for physical activity is
an important factor to consider before, during and after the performance of
any physical activity. If an athlete consumes a lot of sugary foods for instant
energy (simple carbohydrates) this will not be of benefit to them, as this quick
energy burst can result in very low energy levels soon after, as well as cravings
for more. It is far better for an athlete to have a nutritious balance of foods in
their diet to maximise their energy output. They will perform much better, feel
great and as a result be able to maintain a healthier lifestyle.
Role of food as fuel sources
Figure 1.9
Relationship between
carbohydrates, glycogen
and fats
The three main nutrients we consume are carbohydrates, proteins and fats.
The most efficient muscle fuel (or energy source we consume) are complex
carbohydrates, as this nutrient supplies our muscles with glycogen, which
in turn acts as an energy reserve for the muscles. Protein is important for
muscle growth and repair, and fat is used for transportation of hormones and
insulation, and can also be a source of fuel when glycogen stores are depleted
(see figure 1.9).
Carbohydrates
Liver glycogen
Blood glucose
Muscle glycogen
Fat deposits
from The Fitness Leader’s Handbook Egger and Champion, published by Kangaroo Press Anaerobic and aerobic energy production
There are two main classifications for energy systems: the aerobic energy
system and the anaerobic energy system.
Body systems and energy for physical activity
The aerobic energy system is used for long duration or endurance exercise
that uses oxygen to break down glucose. This system is used most often, as we
use it for day-to-day living and basic activities. It is also the most important
energy system for endurance athletes. Most physical activity will commence
with this system and call upon the anaerobic system when faster or more
powerful movement is required.
The anaerobic energy system is used for exercise that involves short duration
or stops and starts. This system is broken into two types. The first is commonly
known as the lactate energy system, which relies on the use of glycogen for
energy, with lactic acid as the by-product. The second type is commonly known
as the phosphate energy system. It relies on stores of creatine phosphate as the
energy source and is used in very fast or explosive movements.
Of these three main ways that our body can make energy for movement,
the energy system that is used is determined by the type, duration (the length
of time) and intensity (how hard) of the exercise performed. Figure 1.10
illustrates the possible energy systems used by the body to move our muscles.
Chapter
1
Figure 1.10
Energy for muscle
contraction
Exercise starts and energy system is recruited
Anaerobic
Aerobic
• Low-intensity exercise
of long duration
Phosphate
Lactate
• Very high intensity exercise
• High-intensity exercise
• 95–100% of maximum effort
• 60–95% of maximum effort
• Explosive activity lasts for
10 seconds
• Duration varies, if exercising at
95% approximately 30 seconds,
and if exercising at 60%
approximately 30 minutes of
exercise can be performed
• Phosphocreatine is the
fuel source
• No waste products
• Very quick recovery—
100% in 2 minutes
• Up to 60% of maximum effort
• Carbohydrates, fat and protein
are the fuels used
• Carbon dioxide and water
are waste products
• Recovery is needed to
replace fuel
• Carbohydrates are the fuel
source, in the form of muscle
glycogen and blood sugar
• Lactic acid is the waste product
• It takes between 20 minutes
and 2 hours to break down
the lactic acid to recover
from The Fitness Leader’s Handbook Egger and Champion, published by Kangaroo Press A combination of these energy systems is used for participation in most
sports or physical activities. For example, an endurance athlete would use the
aerobic system for the majority of a long-distance event but to maintain the
same speed up a steep hill they would need to use the anaerobic lactate or
phosphate systems for a small amount of time. Figure 1.11 indicates how the
energy systems overlap and how all are used to a degree in most sports.
19
20
Move into PASS
PART 1 Foundations of physical activity
Figure 1.11
Contribution of energy
systems to sports events
Energy
contribution
(percent)
100
Oxygen
energy
80
60
40
Lactic
energy
20
Phosphate
energy
0
20 40 60 80 100
150
200
250
300
350
Performance time (seconds)
Running 100 m 200 m 400 m 800 m 1500 m
Swimming
100 m 200 m
400 m
Cycling 1000 m
4000 m
from The Fitness Leader’s Handbook Egger and Champion, published by Kangaroo Press 1 Analyse a sports performance on television, noting the energy system/s
that you think are used by the athletes who participate in this sport.
2 Can you think of any factors that would affect the efficient use of
the energy system in a chosen sport? (For example, environmental
conditions.)
3 Name five physical activities or sports. Identify the energy systems
used in each sport and explain how they are utilised.
Energy input versus energy output
When an athlete is participating in a sport or physical activity, they need to
balance their energy intake (the amount of food and drink consumed) with
their energy expenditure (exercise completed) to maintain a good level of
energy. This is often a fine balance for athletes who have an intense training
program. The basic principle to energy balance is outlined in table 1.2.
Table 1.2
Energy balance
Description of energy balance
Result
Energy expenditure = energy intake
Stable, no change in weight
More energy expenditure + less energy intake
Weight loss
Less energy expenditure + more energy intake
Weight gain
Body systems and energy for physical activity
Chapter
1
Learning experience
1 Participate in a variety of fitness tests and determine the type of energy systems that
you have used for each of the tests. Graph your results using the same format as figure 1.11.
2 Maintaining energy balance can be difficult. It takes a lot of organisation and exercise to keep a
healthy body shape that allows an athlete to participate in the sport of their choice. Referring to
the illustration below, complete the following.
a Give each diagram a title to represent the energy balance or imbalance that is illustrated.
b Write one sentence to explain the balance or imbalance that each diagram represents.
21
22
Move into PASS
PART 1 Foundations of physical activity
Interrelationships between the body systems
Each of the body systems relate to each other and need to function together
for our bodies to perform successfully. There are many other factors that
need to be considered in an athlete’s training program, which are discussed
in chapter 14.
It is vital that our body systems work together to efficiently perform a series
of movements. All athletes rely on energy for their specific sport and the type
of movement carried out will determine the energy system required and the
way in which the body systems adapt to this activity will result in an efficient
performance. A skilled and physically fit body will resemble an efficient
machine that is well hydrated and fuelled, and is geared to automatically
use the most efficient energy system for the task it is about to perform. This
machine will perform well in the pursuit of effective movement during sport
and physical activity if it is well tuned (trained).
The reliance of body systems on each other for
effective functioning
The human body has an amazing capacity to adapt to the demand of
exercise. When a person chooses to exercise, whether this exercise is mild
or extremely active, the human body will activate the circulatory system
(the cardiovascular and respiratory systems), together with the skeletal and
muscular systems, to perform the voluntary movements that create the
actions of an exercise pattern.
The human body and mind work together to allow a person to actively
participate in many activities of choice. Our body systems rely on each
other to work in harmony to move efficiently. An elite athlete, who works
hard to improve their athletic performance through training, will be much
more efficient in activating these body systems than an untrained person
participating in sport for recreation. The type of sport in which a person
participates will also affect the demand that is placed on each system; for
example, an athlete who is a long-distance runner will place much more
demand on their circulatory system than an athlete who is a javelin thrower.
Hydration and physical activity
The term hydration is used to describe the way in which the body uses
and replaces fluid. Our body is made up of approximately 80% water and we
need to keep this level stable or conditions such as dehydration, hyperthermia
or heatstroke can cause health problems and a reduction in performance for
an athlete.
Rapid fluid loss during physical activity can occur and several factors can
increase this fluid loss. For example, humidity, high temperatures and the
consumption of alcohol all cause unnecessary fluid loss.
Body systems and energy for physical activity
Chapter
1
23
Role and importance of water intake during
physical activity
Drinking water or fluids containing water needs to be seriously considered by
anyone participating in physical activity. The regulation of body fluids needs
to be maintained by everyone prior to, during and after physical activity.
If fluid, particularly water, is not consumed by an athlete they can become
dehydrated, and in extreme cases of fluid loss may need medical attention to
replace fluid in the body.
The intake of water to keep well hydrated is very important for everyone
and is especially crucial for endurance athletes. All long-distance (or
endurance) athletes, such as triathletes and marathon runners, need to balance
energy intake with their fluid intake to allow them to perform at their best.
Managing fluid loss and
replacement
While it is important to remain hydrated, the
intake of too much water or weak electrolyte
drinks can also be a danger. Hyponatremia, or
water intoxication, is a very rare condition that can
cause many complications, the worst being death.
During events such as marathons, if too much
water is consumed it cannot be processed by the
body and this is how such complications occur.
Sources of hydration
Water is the best source of hydration for the body.
However, many sports drinks are available and
the market for these drinks is growing, with some
targeting hydration through flavoured waters and
electrolyte drinks. Drinks such as these need to
be chosen carefully and factors such as content,
cost and whether the drink supplies what the body
needs following the specific demands placed on it
by particular sports should be considered.
There are three main types of sports drinks and each one has a different
purpose, depending on the type of training or competition in which an athlete
is participating.
Isotonic drinks are the most common sports drinks, also called electrolyte
drinks. They are designed to quickly replace fluids lost by sweating, as well
as provide a quick fix of glucose.
Hypertonic drinks are used to supplement daily carbohydrate intake. They
are high in carbohydrates. Long-distance or endurance athletes may use
these after an event to help replenish their carbohydrate stores.
Hypotonic drinks are designed to quickly replace fluids lost through
sweating. They are low in carbohydrates and are the most efficient in
replacing fluid and helping to reduce the effects of dehydration.
Figure 1.12
It is important to drink
water or fluids containing
water to remain hydrated
24
Move into PASS
PART 1 Foundations of physical activity
Learning experience
Purpose
To determine the appeal of sports drinks, including the difference between taste, content and
value to hydration of the body during physical activity.
Teacher preparation
Select five to eight different drinks (depending on your class size, time length of the lesson and
budget). Include water, cordial or soft drink and various other sports drinks. The teacher should cover
the label of each drink or place each in a jug and number each one so that the students cannot
identify each drink during the tasting process. Each student will need their own cup.
NOTE: The teacher needs to be aware of and make provisions for any allergies before purchasing and
serving drinks.
Step 1
The teacher pours a small sip of the drinks, one at a time, and communicates the number allocated
to that drink. Students taste the given drink.
Step 2
In a table such as the one below, students record the number of the drink and a description of the
taste (for example, sweet, sour, bitter, etc.).
Step 3
Students give each drink a rating out of 10 for suitability as a sports drink (1 being not suitable for a
sports drink and 10 being very suitable).
Number
Name of the drink
Description
Rating
Step 4
The teacher reveals the names of the drinks and the class inspects the label to analyse contents.
Step 5
Conclude with a class discussion.
Closing question
Which drink do you feel is the best one to hydrate the body after exercise? Why?
Body systems and energy for physical activity
Chapter
1
25
Chapter cloze
When a choice to move is made one or more systems of the
body will be activated to produce a __________ movement.
The _______ _______ is the inner support bone structure for our
body and works together with the efficient system of the heart,
blood vessels and lungs in our body, known as the ______ ______.
The _______ _______ is a voluntary system that requires our will
to move and the central nervous system to send signals from our
brain to the muscle to communicate movement to occur.
When a person participates in physical activity, they may
perform _______ _______, which is exercise of long duration that
uses oxygen as the main energy source, or _______ _______, which
is exercise of short duration that does not use oxygen. Some
physical activities require a combination of both systems.
aerobic exercise
anaerobic exercise
circulatory system
energy expenditure
energy intake
hydration
muscular system
skeletal system
voluntary
Whether a person is an elite or recreational athlete they will
need to take into consideration several factors to maintain efficient
performance. _______ _______ is exercise completed. _______
_______, or fuel, is the amount of food and drink consumed.
The type of exercise and fuel are vital to efficient performance
and a person who wants to perform well will also keep their fluid
intake up as they exercise, to maintain __________ and balance
water loss.
Review questions
1 Briefly describe how bones are held in place.
2 How does oxygen reach the working muscles during exercise?
3 Explain the process of flexion and extension of the hamstring muscles
and give two examples of this movement.
4 Which body system is the most important to exercise? Why?
5 How does an athlete balance their energy to perform well?
Discuss the demands of training and competition in your answer.